Molecular simulations and understanding of antifouling zwitterionic polymer brushes
Molecular simulations and understanding of antifouling zwitterionic polymer brushes
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DOI：
10.1039/d0tb00520g
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发表时间：
2020-05-07
影响因子：
7
通讯作者：
Zheng, Jie
中科院分区：
文献类型：
--
作者：
Liu, Yonglan;Zhang, Dong;Zheng, Jie
两性离子材料是一类应用广泛的生物防污材料。尽管有这些理想的防污性能，但分子水平上对表面化学/拓扑/水合作用和防污性能的结构-性质关系的了解仍有待阐明。本文采用分子力学(MM)、蒙特卡罗(MC)、分子动力学(MD)和定向分子动力学(SMD)模拟相结合的方法，对三种两性离子聚合物刷--聚甲基丙烯酸羧酸甜菜碱(PCBMA)、聚甲基丙烯酸磺基甜菜碱(PSBMA)和聚甲基丙烯酸磺基甜菜碱(poly((2-(methacryloyloxy)ethyl)phosporylcoline))的聚乙二醇刷的堆积结构、表面水化和防污性能进行了计算研究。在复杂的能量环境中，我们首次确定了来自各种晶胞和链取向的所有聚合物刷子的最佳堆积结构。在优化的堆积结构下，进一步用分子动力学模拟研究了水分子和蛋白质在四种聚合物刷子上的吸附结构、动力学和取向，并用SMD模拟研究了聚合物刷子对蛋白质的表面阻力。集体结果一致地表明，三种两性离子刷子与水分子的相互作用更强，对蛋白质的表面电阻比聚乙二醇刷更高。结果表明，两性离子基团之间的碳空间长度和阴离子基团的性质都对阻垢性能有明显的影响，导致pCBMA>；pMPC>；pSBMA的阻垢性能排序如下。这项工作有望为超越传统的聚乙二醇基防污材料的新型防污材料的设计提供一些结构性的见解。
Zwitterionic materials are an important class of antifouling biomaterials for various applications. Despite such desirable antifouling properties, molecular-level understanding of the structure-property relationship associated with surface chemistry/topology/hydration and antifouling performance still remains to be elucidated. In this work, we computationally studied the packing structure, surface hydration, and antifouling property of three zwitterionic polymer brushes of poly(carboxybetaine methacrylate) (pCBMA), poly(sulfobetaine methacrylate) (pSBMA), and poly((2-(methacryloyloxy)ethyl)phosporylcoline) (pMPC) brushes and a hydrophilic PEG brush using a combination of molecular mechanics (MM), Monte Carlo (MC), molecular dynamics (MD), and steered MD (SMD) simulations. We for the first time determined the optimal packing structures of all polymer brushes from a wide variety of unit cells and chain orientations in a complex energy landscape. Under the optimal packing structures, MD simulations were further conducted to study the structure, dynamics, and orientation of water molecules and protein adsorption on the four polymer brushes, while SMD simulations to study the surface resistance of the polymer brushes to a protein. The collective results consistently revealed that the three zwitterionic brushes exhibited stronger interactions with water molecules and higher surface resistance to a protein than the PEG brush. It was concluded that both the carbon space length between zwitterionic groups and the nature of the anionic groups have a distinct effect on the antifouling performance, leading to the following antifouling ranking of pCBMA > pMPC > pSBMA. This work hopefully provides some structural insights into the design of new antifouling materials beyond traditional PEG-based antifouling materials.